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Performance of bearing-only ESM-radar track associationhttp://dl-live.theiet.org/content/conferences/10.1049/cp.2012.0409
The bearing-only association of tracks from dissimilar sensors is considered, in particular the association of radar and electronic support measures (ESM) tracks. An approach to characterising performance is suggested, namely the curve representing the relationship between the median time to reach a correct association decision and the mean number of incorrect associations, as the association threshold is varied. Results are presented for artificially generated tracks, showing the variation of performance with track density and accuracy. Results are also given for the association of real radar tracks of ships with simulated ESM tracks. In particular, it is concluded that the ability to attach identity information from ESM to long-range radar tracks will be significantly improved if the ESM bearing errors are reduced, for example from a magnitude of order 50° to 10°. (6 pages)Gaussian mixture PHD filter for multi-target tracking using passive Doppler-only measurementshttp://dl-live.theiet.org/content/conferences/10.1049/cp.2012.0417
In this paper, we analyze the performance of the Gaussian mixture probability hypothesis density (GM-PHD) filter in tracking multiple non-cooperative targets using a passive sensor network. Non-cooperative transmissions from illuminators of opportunity like GSM base stations, FM radio transmitters or digital broadcasters are exploited by non-directional separately located Doppler measuring sensors. Clutter, missed detections and multi-static Doppler variances are incorporated into a realistic multi-target scenario. Simulation results show that the GM-PHD filter success fully tracks multiple targets using only Doppler shift measurements in a passive multi-static scenario. (6 pages)Track degradation as a consequence of distributed sensor fusionhttp://dl-live.theiet.org/content/conferences/10.1049/cp.2012.0408
It is often taken for granted that measurement-level data fusion must necessarily give rise to an improvement in the track picture, particularly in situations where the sensors are spatially distributed. In many cases, this assumption is justified - an obvious example is where each sensor individually produces too sparse a set of plots to support a track, whereas multiple sensors can provide a sufficient density of measurements. Another example is where complementary viewing angles can permit more precise target localisation. There are, however, situations in which the provision of information from multiple sensors can actually be detrimental to the tracking of closely-spaced objects. This behaviour has been observed using very high-fidelity simulations of a set of high-range-resolution radars observing closely-spaced ballistic targets. It is shown that the complementary viewing angles provided by distributed sensors can actually increase the likelihood of miscorrelation, in situations in which the closely-spaced objects (CSOs) are resolvable in range but not in angle. An attempt to exploit the individual sensor resolution capabilities by using track-associated plot processing was found to be fragile. An MHT (Multi-Hypothesis Tracking) approach, however, is shown to be a robust solution. (6 pages)Optimized instrumental density for particle filter in track-before-detecthttp://dl-live.theiet.org/content/conferences/10.1049/cp.2012.0418
In this paper, we address the problem of the detection and tracking of a single target in Track-Before-Detect with a particle filter from radar measures. The studied particle filter solves the detection problem by introducing a Markovian variable that stands for the presence or absence of the target. We claim that the usual prior density used as instrumental density is not suitable here, and we propose an efficient particle filter based on a relevant proposal density based on detection and estimation considerations that aims at extracting all the available information from the measurements. This filter leads to dramatically improved performance compared to the particle filter based on the classic instrumental distribution, both in terms of detection and estimation. (6 pages)Noise power estimation under generalized detector employment in automotive detection and tracking systemshttp://dl-live.theiet.org/content/conferences/10.1049/cp.2012.0416
The noise power estimation process is a vital factor to adaptively define a threshold of target return signal in radar sensor systems and controller area networks (CAN) that are employed to design safety driving applications, collision avoidance systems, and target vehicle tracking systems. This research derives the required detection threshold under implementation of the generalized detector (GD) in frequency modulation continuous wave (FMCW) radar sensor systems for safety driving and tracking applications, for example, under closing vehicle detection. In this paper we propose an appropriate adaptive noise power estimation technique to define the GD threshold based on locally observed noise samples. The improvement in the detection performance reflects an effectiveness of the proposed solution. (4 pages)Waveform Design and Diversity for Advanced Radar Systemshttp://dl-live.theiet.org/content/books/ra/pbra022e
<p xmlns="http://pub2web.metastore.ingenta.com/ns/">The phrase 'waveform design and diversity' refers to an area of radar research that focuses on novel transmission strategies as a way to improve performance in a variety of civil, defense and homeland security applications. Three basic principles are at the core of waveform diversity. First is the principle that any and all knowledge of the operational environment should be exploited in system design and operation. Second is the principle of the fully adaptive system, that is, that the system should respond to dynamic environmental conditions. Third is the principle of measurement diversity as a way to increase system robustness and expand the design trade space. Waveform design and diversity concepts can be found dating back to the mid-twentieth century. However, it has only been in the past decade or so, as academics and practitioners have rushed to exploit recent advances in radar hardware component technology, such as arbitrary waveform generation and linear power amplification, that waveform diversity has become a distinct area of research. The purpose of this book is to survey this burgeoning field in a way that brings together the diverse yet complementary topics that comprise it. The topics covered range from the purely theoretical to the applied, and the treatment of these topics ranges from tutorial explanation to forward-looking research discussions. The topics treated in this book include: classical waveform design and its extensions through information theory, multiple-input multiple-output systems, and the bio-inspired sensing perspective; the exploration of measurement diversity through distributed radar systems, in both cooperative and non-cooperative configurations; the optimal adaptation of the transmit waveform for target detection, tracking, and identification; and more. This representative cross-section of topics provides the reader with a chance to see the three principles of waveform diversity at work, and will hopefully point the way to further advances in this exciting area of research.</p>Characterization of vibrating targets in bistatic SARhttp://dl-live.theiet.org/content/conferences/10.1049/ic.2011.0146
Motions and micro-motions of objects in an illuminated scene introduces Doppler and micro-Doppler effects in the received echoes. Combining the advantages introduced by the bistatic SAR (BSAR) configuration and the usefulness of the micro-Doppler signature characterization will provide a powerful tool for military and civil applications such as target recognition and classification. In this paper a vibrating micro-Doppler signature for a BSAR system with fixed receiver is analyzed and compared to the signature obtained in a monostatic SAR system. The micro-Doppler effect in a Bistatic SAR system for vibrating targets is analyzed and the derived mathematical model is confirmed with simulations. (5 pages)Time-reversal-based multipath mitigation technique for entropy minimization of SAR imageshttp://dl-live.theiet.org/content/conferences/10.1049/ic.2011.0139
Synthetic Aperture Radar (SAR) images a target region reflectivity function in the multi-dimensional spatial domain of range and cross-range with a finer azimuth resolution than the one provided by any on-board real antenna. Conventional SAR techniques just consider a single reflection of transmitted waveforms from targets. Nevertheless, today's new applications force SAR systems to work in much more complex scenes such as urban environments. Consequently, multiple- bounce returns are additionally superposed to direct-scatter echoes. We refer to these as ghost images, since they obscure true target image and lead to poor resolution. By applying Time Reversal concept to SAR imaging (TR-SAR), it is possible to reduce considerably -or even mitigate-ghosting artifacts, recovering the lost resolution due to multipath propagation. Furthermore, some focusing indicators such as entropy (E), contrast (C) and Rényi entropy (RE) provide us with a good focusing criterion when using TR-SAR. (5 pages)NG-distribution radar sea clutter embedded with thermal noisehttp://dl-live.theiet.org/content/conferences/10.1049/ic.2011.0166
In this paper we investigate and study the performance of a high resolution cell-average constant false alarm rate (CA-CFAR) radar of a Swerling II target embedded in sea clutter plus additive Gaussian thermal noise. The sea clutter is modelled as NG-distribution. Closed form expressions for probabilities of false alarm and detection are derived. Also, Monte Carlo simulations are carried out to assess the system performance both theoretically and by simulations. (4 pages)A new penetration route planning method based on the dynamic aircraft RCS modelhttp://dl-live.theiet.org/content/conferences/10.1049/ic.2011.0147
The survivability of aircraft can be enhanced by appropriate penetration route planning method. The existing model of the operation space for route planning can not reflect exactly all characteristics of the radar threat environment. This paper proposed a new method for radar modeling by introducing the artificial potential field (APF) approach for robot route planning. In view of the variation of the radar threat environment according to the different observed radar cross sections (RCS) during each time interval, the dynamic aircraft RCS model was proposed, and the dynamic APF model of radar threat for route planning was built on this RCS model. Additionally, a RCS data process program is applied to satisfy the real-time requirement of route planning. The simulation results indicated that this new kind of model can reflect the variation of radar threat environment during the penetration phase and the obtained penetration route is more rational. (5 pages)Sparsity-aware STAP algorithms for airborne radar based on conjugate gradient techniqueshttp://dl-live.theiet.org/content/conferences/10.1049/ic.2011.0142
In this paper, new sparsity-aware space-time adaptive processing (STAP) algorithms based on conjugate gradient (CG) techniques are proposed. The idea of sparsity-aware STAP algorithms is based on the incorporation of a sparse regularization (l<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">1</sub>-norm) constraint to the minimum variance (MV) design criterion. To solve this optimization problem, two different l<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">1</sub>-based algorithms based on the conventional CG and the modified CG are derived. An analysis of the computational complexity shows that the proposed algorithms have nearly the same cost as the conventional algorithms. It is also demonstrated that the proposed STAP algorithms outperform the conventional algorithms using the simulated airborne radar data. (5 pages)Transmit beamforming for range ambiguous clutter mitigation in forward-looking STAP radarhttp://dl-live.theiet.org/content/conferences/10.1049/ic.2011.0162
In forward-looking space-time adaptive processing (STAP) radars, range ambiguity causes range bins far from the target of interest to contribute additional energy to the target range cell and training data. This additional energy can severely degrade target detection performance due to the different angle-Doppler characteristics of the clutter. In this work, we study the use of transmit beamforming to help overcome this problem by designing an elevation beampattern which does not illuminate the ambiguous ranges. This beampattern design has a low complexity solution and provides improvements in clutter training data homogeneity and total received clutter energy. (4 pages)Remote sensing of a geographical environment with portable radars and satellite linkhttp://dl-live.theiet.org/content/conferences/10.1049/ic.2011.0064
The environments such as inaccessible places in forests and deserts obstruct free access to human beings and call for remote access by electronic means to get the geographical nature. This research project deals with the establishment of a system for remotely sensing and gathering the information. Three locations, which reveal the geography in a better manner is decided first and three portable radars are launched into the spots from air As soon as the radars stabilize their positions they start functioning to scan electronically the environment. Beam sweeping is performed for complete coverage of 360 degrees and the action is repeated continuously to get the PPI information of the surroundings. The target information collected at these radar receivers are transferred to satellite link through distributed wireless sensor network. In the remote ground station the information from three radars are processed to extract information about the static and moving objects in the spotted area.DOA estimation in MIMO radar based on coherent signal-subspace method [signal read signal]http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0840
MIMO radar in this paper uses sparse-array to transmit the FMCW signals of multiple carrier frequencies, and an array to receive the echoes. Due to transmit signals of multiple carrier frequencies, the Doppler frequency of the received signals after separated is not in a Doppler cell, and then the traditional supper-resolution algorithms work ineffectively, the parameters of the target can't be obtained. One method is presented in this paper. Firstly the data of different frequency is transformed into the data of the same frequency using focusing transformation, and then the spatial spectrum estimation algorithms are applied. The simulation results indicate the validity of the methods presented in this paper.Characterisation of ballast materials in trackbed using ground penetrating radar: Part 1http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.0593
In recent years the use of high frequency GPR antennas such as the 2GHz horn antenna have become popular for railway trackbed evaluation due to their ability to help determine the extent of fouling within the ballast layer. Fouling of the ballast affects both its strength and drainage properties. The theory is based on the scattering behaviour of GPR signals in an inhomogeneous media, comprising evenly distributed particles and air voids. Whilst GPR has been successfully implemented as a tool for mapping ballast quality, the relation between the GPR scattering response and the physical properties of the ballast and fouling materials have not been examined and studied in detail up until now the method has been mainly empirical, based on measured correlations. This paper conducts an investigation of the GPR scattering response to the railway ballast aggregate layer by providing a comprehensive study of factors affecting the radar signal including; ballast grading (particle size distribution), particle shape, void size and the electromagnetic properties of the ballast (dielectric, conductivity, magnetic permeability). Sample analysis, numerical simulations, laboratory tests and real-world data collection have been conducted in this research. Detailed analysis and discussions are provided on factors contributing to the observed signal scattering and attenuation. This is the first in a series of papers looking at the influence of various factors on the response of GPR within ballasted trackbed. (8 pages)Fractional Fourier transform based monopulse radar for combating jamming interferencehttp://dl-live.theiet.org/content/conferences/10.1049/ic.2010.0221
Monopulse radars are used to track a target that appears in the look direction beam width. The distortion produced when manmade high power interference (jamming). Jamming scenarios are achieved by introducing high power interference to the radar processor through the radar antenna main lobe (main lobe interference) or antenna side lobe (side lobe interference). This leads to errors in the target tracking angles that may cause target mistracking. A new monopulse radar structure is presented in this paper which offers a solution to this problem. This structure is based on the use of optimal Fractional Fourier Transform (FrFT) filtering. The proposed system configurations with the optimum FrFT filters is shown to reduce the simulated interfered signal and improve the signal to noise ratio (SNR) in the processors outputs in both processor using the proposed monopulse structure. (5 pages)Maximum likelihood sub-arrayed MIMO radar receiverhttp://dl-live.theiet.org/content/conferences/10.1049/ic.2010.0240
There has been recent interest in MIMO radars which employ sub-arrays at the transmitter. This architecture allows a trade-off between the coherent beamforming gain of a phased array antenna and the transmit beampattern diversity offered by a MIMO radar with full transmit diversity, while maintaining a relatively simple implementation in the transmit hardware. In this work we study the maximum likelihood (ML) receiver for a transmit sub-arrayed MIMO radar, for estimating the direction of arrival of multiple targets. We develop the likelihood function for an orthogonal sub-arrayed MIMO radar for receiver architectures with and without a matched-filter bank. The maximisation of these likelihood functions form multi- dimensional optimisation problems which can be solved using a variety of sub-optimal numerical algorithms. (5 pages)Radar matched filtering using the fractional fourier transformhttp://dl-live.theiet.org/content/conferences/10.1049/ic.2010.0242
A matched filter is the optimal linear filter for maximizing the signal to noise ratio (SNR) in the presence of additive noise. Matched filters are commonly used in radar systems where the transmitted signal is known and may be used as a replica to be correlated with the received signal which can be carried out by multiplication in the frequency domain by applying Fourier Transform (FT). Fractional Fourier transform (FrFT) is the general case for the FT and is superior in chirp pulse compression using the optimum FrFT order. In this paper a matched filter is implemented for a chirp radar signal in the optimum FrFT domain. Mathematical formula for a received chirp signal in the frequency domain and a generalized formula in the fractional Fourier domain are presented in this paper using the Principle of Stationary Phase (PSP). These mathematical expressions are used to show the limitations of the matched filter in the fractional Fourier domain. The parameters that affect the chirp signal in the optimum fractional Fourier domain are described. The performance enhancement by using the matched filter in the fractional Fourier domain for special cases is presented. (5 pages)Knowledge-aided STAP algorithm using affine combination of inverse covariance matrices for heterogenous clutterhttp://dl-live.theiet.org/content/conferences/10.1049/ic.2010.0241
By incorporating a priori knowledge into radar signal processing architectures, knowledge-aided space-time adaptive processing (KA-STAP) algorithms can offer the potential to substantially enhance detection performance and to combat heterogeneous clutter effects. In this paper, we develop a KA-STAP algorithm to estimate directly the interference covariance matrix inverse rather than the covariance matrix itself, by using a linear combination of inverse covariance matrices (LCICM), which leads to an equivalent expression of the combination of two filters. The computational load is greatly reduced due to the avoidance of the matrix inversion operation. The performance of the LCICM scheme can be further improved by applying a modification. Moreover, adaptive algorithms for the mixing parameters are developed using affine combinations (AC). Numerical examples show the potential of our proposed algorithms for substantial performance improvement. (5 pages)Fractional RDA and enhanced FrCSA for SAR imaginghttp://dl-live.theiet.org/content/conferences/10.1049/ic.2010.0243
Synthetic Aperture Radar systems are used to form high resolution images from radar backscattered signals. The Fractional Fourier transform (FrFT), which is a generalized form of the well-known Fourier transform, has opened up the possibility of a new range of potentially promising and useful applications that involve the use and detection of chirp signals including pattern recognition and SAR imaging. In this paper the FrFT is applied to the well established Range Doppler Algorithm and to the Chirp Scaling Algorithm to form the FrRDA and eFrCSA (enhanced Fractional CSA). The performance of the algorithms are assessed using simulated and real Radarsat-1 data sets. The results confirm that the FrFT based SAR processing methods provide enhanced resolution yielding superior focusing accuracy and target detection. (5 pages)Reduced-rank STAP for airborne radar based on switched joint interpolation, decimation and filtering algorithmhttp://dl-live.theiet.org/content/conferences/10.1049/ic.2010.0245
We present an adaptive reduced-rank signal processing technique for airborne phased array radar applications. The proposed method performs dimensionality reduction by using a reduced-rank switched joint interpolation, decimation and filtering algorithm (RR-SJIDF). A multiple-processing-branch (MPB) framework, which contains a set of jointly optimized interpolation, decimation and filtering units, is employed to process the observations. The output is switched to the branch with the best performance among the available ones. In order to design the decimation unit, we present the optimal decimation scheme and also a low-complexity decimation algorithm. We then develop a low-complexity recursive least squares (RLS) algorithm for the proposed scheme. Simulations results show that the proposed RR-SJIDF STAP algorithm converges at a very fast speed and provides a considerable signal-to-interference-plus- noise-ratio (SINR) performance improvement over the state-of- the-art reduced-rank schemes. (5 pages)Processing three-channel SAR-ATI for GMTIhttp://dl-live.theiet.org/content/conferences/10.1049/ic.2010.0222
This paper investigates two methods for GMTI using three-channel SAR-ATI data. Motivated by previous results in the two-channel case, a deterministic method for finding an Eigendecomposition of the SAR-ATI sample covariance matrix is presented. The CFAR detection capability of each of the eight parameters of the Eigendecomposition is evaluated using measured three-channel airborne data and compared to the well- known DPCA-ATI metric. Results suggest that all moving target energy is contained in a single parameter, the largest Eigenvalue, and that for a given theoretical CFAR a lower real-world false alarm rate is achieved in comparison to DPCA-ATI. Motivated by this result ICA is then applied to the same measured three- channel data and found to both detect and distinguish two different types of moving target simultaneously present in a maritime environment. (5 pages)Evaluation to the performance of MTI radar antipassive jamminghttp://dl-live.theiet.org/content/conferences/10.1049/cp.2010.0671
The signal processing elements and working course of MTI radar are analyzed in this paper, and theory research is also done to the element and performance of double canceller. Aiming at the Gaussian power-spectral clutter with differ velocity value and variance, this paper calculates the performance of MTI system quantitatively and the corresponding improvement factor of anti-passive jamming is achieved, the performance of MTI radar is estimated synthesized.Automated indicators for behavior interpretationhttp://dl-live.theiet.org/content/conferences/10.1049/ic.2009.0258
While sensors become distributed at an unprecedented scale, their use in the monitoring of hostile activities is very limited. Monitoring by humans is demanding and expensive. To aid in the complex and semantic task of deciding whether a situation implies hostile intent, the authors describe a set of automated behavioral indicators based on camera and radar data. (6 pages)Feature extraction of cone with precession based on micro-Dopplerhttp://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0272
Precession is a key feature for distinguishing warhead from decoys in the missile mid course, and a method of feature extraction of target with precession based on the micro-Doppler modulation is provided in this paper. The radar echo model of cone with precession is simulated by point scattering model, and the modulation of Doppler frequency caused by precession is developed. As the spread of echo spectrum corresponding to the modulation amplitude of micro-Doppler frequency, a method utilizing the spread of echo spectrum is provided to estimate the precession angle. Based on the characteristics of micro-Doppler, a 2D reconstruction of the target using inverse Radon transform and time-frequency distribution is proposed. The experiments demonstrate the validation of proposed method. (5 pages)A method of angle error extraction for monopulse radar with 3-subarray variable polarization antennahttp://dl-live.theiet.org/content/conferences/10.1049/cp.2009.1251
To improve the ability of radar's anti-jamming and target recognition, polarization technology is applied to monopulse angle measurement. 3-subarray millimetre wave variable polarization array antenna is also proposed and discussed in this paper. A novel method of angle error extraction in horizontal and vertical direction is given by analyzing polarization synthesis and electric field of the antenna, meanwhile, the difference between the new method and traditional one is discussed. Finally, according to the new method, simulation results of angle error extraction are presented.Efficient subspace-based recognition method for SAR targets with similar structurehttp://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0117
To identify target for the images obtained by synthetic aperture radar (SAR), those subspace-based methods for automatic target recognition (ATR) usually operate on the range subspace of the training samples. When some targets with similar structures need to be distinguished, the corresponding templates are poorly separable because their range subspaces of each other have a big intersection. A method is proposed for SAR target ATR in this paper, which chooses the orthogonal subspace of the sample range subspace as the projection subspace. Consequently, the difference, between the projections of the different type targets on the projection subspace, is enlarged, which significantly improves the identification effect. Experimental results show that the proposed method is superior to the other similar methods. (4 pages)The synthetic aperture radar trans- ionospheric radio propagation simulator (SAR-TIRPS)http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0046
Space-based synthetic aperture radars (SAR) operating below 1 GHz are subject to forward scattering by ionospheric irregularities. This limits the synthetic aperture and bandwidth over which phase coherence can be maintained. This paper describes the SAR trans-ionospheric radio propagation simulator (SAR-TIRPS), a phase screen model which simulates ionosphere-corrupted SAR images of point targets. The Parabolic Equation propagation method allows both phase and amplitude fluctuations to be modelled. Background Total Electron Content (TEC) is modelled as an additional frequency-dependent phase shift. Examples are presented of L-band and P-band SAR simulations, showing how the target image and derived quantities (sidelobe ratios along- and cross-track) vary with changing ionospheric phase spectrum parameters. SAR-TIRPS proves to be a useful tool in assessing design concepts for low-frequency space radars.A novel three-dimensional coverage visualization system of netted radars based on ArcObjectshttp://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0220
This paper provides the detailed architecture designs and realization steps for a novel three-dimensional coverage visualization system of netted radars based on ArcObjects. The proposed system can provide the visualized 2D and 3D diagrams and quantitative analysis for radar coverage with considerations of the earth curvature and atmospheric refraction. Especially, the real terrain masking and the electromagnetic jamming are also included for the real coverage computation. Finally, an example is provided to demonstrate effectiveness of the proposed system. (5 pages)Barrage noise jamming suppression methods for airborne phased array radarhttp://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0291
Barrage noise jamming is the most important jamming form for airborne phased array radar. In this paper, the characteristic of barrage noise jamming is analyzed firstly. Secondly, the theory, advantage and disadvantage of existing jamming suppression methods are analyzed according to simultaneous suppression form or cascaded suppression form. Finally, the performance of jamming suppression methods is compared by simulation, and the computational load of jamming and clutter suppression methods is presented. (6 pages)Bistatic hybrid spaceborne/airborne SAR: inverse sliding spotlight imaginghttp://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0301
Hybrid spaceborne/airborne bistatic SAR has been focused in bistatic SAR research. Considering the great differences between the velocity of satellite and airplane, receiver operates in the inverse sliding spotlight mode. This paper discussed the special geometry of hybrid spaceborne/airborne bistatic SAR, as well as the variation of azimuth resolution. The equivalent two-dimensional spectrum is obtained using the "Single-line range model", and then the variant equivalent parameters are approximated with the average equivalent parameters. In the end, the monostatic NCS algorithm is applied to imaging. Simulated result shows that the equalization is effective. (5 pages)Micro-Doppler analysis of high speed moving targetshttp://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0283
Micro-Doppler induced by mechanical vibrating or rotating of structures in a radar target is potentially useful for target detection, classification and recognition. While the Doppler frequencies induced by the target body scatterers are constants after motion compensation, the micro-Doppler due to vibrating or rotating structures of the target is a function of dwell time. Now the characteristic of micro-Doppler has been used in low speed moving targets' recognition widely, but high speed moving targets have different properties from the low speed moving targets. Due to the influence of high speed, the returned signal after stretch processing will appear range profile broadening and range migration. This paper analyzes the micro-Doppler signature of high speed moving targets, and computer simulations are given to prove the validity of the analysis. (4 pages)A W-KNN classifier to improve radar outlier rejection performancehttp://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0106
Radar automatic target recognition (ATR) mainly corresponds to uncooperative targets, and the training database is usually incomplete. So in the test step, we should reject the targets with new class labels as outliers firstly, and then recognize the remaining targets (inners) in detail. Combining with engineering application, we proposed a reasonable method to artificially generate outliers and designed a weighted KNN (W-KNN) classifier to treat with the outlier rejection problem. Experiments conducted on high-resolution range profiles (HRRP) data show that the W-KNN classifier is a promisingly method to treat with the rejection problem. (4 pages)Improved Doppler parameters' estimation for ScanSAR datahttp://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0455
Estimation of Doppler centroid and Doppler rate is important for spaceborne synthetic aperture radar system. An improved method for Doppler parameters' estimation based on special mode of ScanSAR is presented in this paper. Differing from the traditional estimating method, Doppler centroid and Doppler rate are estimated in same process using fractional Fourier transform. It has less computing complexity and is proved accurate by simulation. (3 pages)A method for accuracy improvement for LFM parameters estimationhttp://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0434
This paper introduces a method which can improve accuracy for estimating parameters of linear frequency modulation (LFM) signal. The proposed approach is based on Short Time Fourier Transform (STFT). After STFT, spike filter and detecting threshold are used to achieve high precision of parameters estimation in the time domain. What's more, moving windows and frequency compensation are done to improve accuracy for frequency parameters estimation. Simulation results show that this method is effective in improving the accuracy for parameters estimation of LFM and requires only moderate computation ability. Thus it can be widely applied. (4 pages)Efficient demodulation method for FMCW radar systemhttp://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0129
An efficient demodulation method designed for high frequency surface wave radar system is presented, which is a modified SRC (sampling rate conversion) algorithm without any anti-aliasing filter used inside. This paper demonstrates the new method by analyzing the structure of FMCW (Frequency-modulated continuous wave) radar and the computing complexity compared with the traditional methods is given. The algorithm has been implemented in our newly designed HF radar system. (4 pages)Power combined tube transmitters with graceful degradationhttp://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0019
This paper describes power combined microwave tube transmitters for very high peak and average power, with the attribute of graceful degradation. This technology replaces single high power microwave tubes (which have low Mean Time Between Critical Failures, and consequently poor Availability), and provides a lower cost and higher efficiency solution compared to solid state. (4 pages)A new algorithm improving SAR resolution based on SVAhttp://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0320
Resolution enhancement techniques in radar imaging have attracted considerable interest in recent years. The paper develops a new technique enhancing SAR resolution as well as suppressing sidelobes based on SVA technique. Spatially variant apodization (SVA) is a nonlinear sidelobe reduction method without lose the resolution of mainlobe. The signal bandwidth is extrapolated after SVA, which is the basis of resolution enhancement. An inverse weight function is used to equalize the SVA spectrum. A modified noninteger Nyquist spatially variant apodization (SVA) formulation is used to suppress sidelobes after extrapolation. Examples of ID case and 2D case demonstrate enhanced image resolution with sidelobe reduction. (4 pages)New approach of fast matrix access for real-time SAR systemhttp://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0388
Based on the analyzing read-and-write features for synthetic aperture radar real-time processing and synchronous dynamic random access memory, an optimized fast matrix access algorithm is presented. The new method has been implemented on TS201 processing platform, which is used to process radar signal. Based on the analysis of experiment, it can be known that this new algorithm can achieve a constant speed and high efficiency for matrix access without altering bus data rate. The efficiency of real-time SAR system can be increased because of using the new approach of matrix access. (4 pages)Poly-phase encoded waveform optimal design for space-borne MISO radar systemshttp://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0323
The application of multiple input techniques to sparse space- borne radar offers a number of advantages, including mitigating the effect of the target scintillation and being more freedom of signal processing. A novel orthogonal poly-phase encoded waveform optimization design method is presented. It is combined the genetic algorithm (GA) with the frequency functions designed by window functions to reduce the computation complexity. For the radar system, multiple transmissions of orthogonal coding signal and single reception, the high ISL of the optimized waveforms may cause degradation of the detection performance of the ground moving target. So, there is a trade-off optimization between the orthogonality and side-lobes of the signals. Simulation results show the effect of the transmission waveforms characteristic on the system's detection performance. (5 pages)Research on detection algorithm of high-speed and low-observable targetshttp://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0349
Both ballistic missiles in midcourse trajectory and space debris have the characteristics of small RCS and high speed, which would be difficult to be detected by the warning radar system. In this paper, based on analyzing the influence of the velocity on high-speed and low-observable target's detection, Keystone Transformation technique is presented to correct the influence of velocity. Finally, according to the system parameters of Cobra Dane radar, simulation is implemented to verify the coherent accumulation based on Keystone Transformation, whose performance is also compared with the coherent accumulation based on Envelope Alignment. (4 pages)Interferometric ISAR imaging for RCS and three-dimensional target characteristics measurementshttp://dl-live.theiet.org/content/conferences/10.1049/cp.2009.1296
Target characteristics are measured using variable methods, interferometric ISAR technology is used to get three dimension signature and RCS from a target. The model of interferometric ISAR is set up, the structure of the system with a single transmitter and two receivers is designed. Then eight scatterers model is supposed, two ISAR images can be got at the same time after the back projection reconstruction algorithm, and the inteferometric image can be got. Numerical simulation verifies that this method is available.A 2-D correlated noise depressive jamming technique to synthetic aperture radarhttp://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0378
A new correlated noise depressive jamming (COR-NDJ) technique is proposed to improve the performance of the common noise depressive jamming (COM-NDJ) to synthetic aperture radar (SAR). Based on the false target deceptive jamming (FTDJ) principle, the COR-NDJ signal generation is discussed. Simulation results show that the 2-D COR-NDJ performs much better than COM-NDJ technique. (4 pages)3-D ISAR imaging reconstruction of non-uniformly rotating targets with FRFT techniquehttp://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0468
In this paper, a novel 3D ISAR image reconstruction method based on FRFT is proposed. Although the RID algorithm, based on time-frequency analysis, has been used to improve the 2D image of the non-uniformly rotating target, the 3D image reconstruction is difficult for the conventional time-frequency analysis method. To solve this problem, we introduce the FRFT technique to reconstruct the 3D ISAR image of the non-uniformly rotating target. For its good property, the high resolution 2D image can be achieved effectively, as well as the interferometric phase difference can be extracted easily. So the final 3D ISAR image of the non-uniformly rotating target can be reconstructed effectively. (4 pages)Research on knowledge-based STAP technologyhttp://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0348
Great progress has been made in the STAP technique with the decades development, but some problems are still faced in the real application. Firstly a knowledge-based (KB) STAP technique was introduced in this paper. And then several applications were investigated in detail, and the key problems of developing KB STAP are analyzed. Finally, some advices were given. (4 pages)A tri-look detector for single channel SAR-GMTIhttp://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0277
This article studies clutter suppression and detection of moving targets in single channel SAR images. By analysing the most commonly used 3-channel SAR-GMTI principle, a new detector based on tri-look image Cancellation-After-Interferometry (CAI) is proposed where tri-aperture images are constructed by overlapped frequency even-partition of clutter bandwidth. Compared with the single channel SAR detector such as traditional tri-aperture cancellation, simulation results show the proposed algorithm having better robustness against clutter uncertainty especially in strong clutter environments and having capability of detection those with azimuth velocity vector. The simulation and performance comparison with 3-channel detection method also show that the proposed algorithm has no direct capability of parameter estimation resulted from phase randomness in single channel deployment. (5 pages)FPGA implementation of SNR estimation for DSSS signal of space borne secondary radarhttp://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0483
According to the problem of SNR estimation for DSSS signal in space borne secondary radar, an efficient approach has been presented. For the implementation of real-time processing of SNR estimation, the efficiency is improved by the redesign of the algorithm flow. Moreover, the SNR estimation is accomplished on a large-scale programmable gate array with the capability of processing high resolution. Simulation results indicate that the principle of the method is correct. Taking into account the space condition, the method performs well. (4 pages)Diagonal clustering-based discriminant analysis for synthetic aperture radar automatic target recognitionhttp://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0282
A novel subspace analysis method called diagonal clustering- based discriminant analysis (DiaCDA) is proposed. Unlike principal component analysis (PCA), fisher linear discriminant (FLD) and clustering-based discriminant analysis (CDA), DiaCDA directly seeks the optimal projection vectors from 2-dimensional diagonal image matrices not from 1-dimensional original image vectors. Moreover, the advantage of DiaCDA over 2-dimensional PCA (2DPCA), 2-dimensional FLD (2DFLD) and 2- dimensional CDA (2DCDA) is that DiaCDA seeks the projection vectors by interlacing both row and column information of the original images, while 2DPCA, 2DFLD and 2DCDA seek the projection vectors by using only row information of the original images. Experimental results conducted on the moving and stationary target acquisition and recognition (MSTAR) public database show that DiaCDA has obtained higher recognition rates or at least the same ones as 2DPCA, 2DFLD, and 2DCDA. In addition, the recognition performances can be further improved and feature dimensions can be reduced sharply by combining DiaCDA with 2DCDA. (4 pages)Research on invariant imbedding method of velocity ambiguity resolutionhttp://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0226
Velocity ambiguity exists in pulse Doppler radar. The differentiation of range data can be used to resolve velocity ambiguity, but the differentiation is not exact because of the measurement error of range data. A novel method called invariant imbedding method which uses range data to resolve velocity ambiguity is proposed. This method is combined with weighting function, and then the final result is easy to apply. The theoretical analysis and simulation prove that invariant imbedding method is effective in velocity ambiguity resolution, and invariant imbedding method can get the target position perfectly. The influence of acceleration on invariant imbedding method is derived. (4 pages)A track alignment-correlation algorithm with systematic errors in radar networkhttp://dl-live.theiet.org/content/conferences/10.1049/cp.2009.0408
This paper has researched on the problem of track correlation with systematic errors in radar network, and analyzed that how does the systematic errors affect the detected tracks of target theoretically. On the basis, prior to registration, a track alignment-correlation algorithm based on Fourier Transform has been presented. The algorithm estimates the rotation and translation amount by using the Fourier Transform, and aligns the track data of targets reported by radars in the network, can correlate the track accurately without registration, and provide reliable correlated tracks for the next registration. (4 pages)